On The Practical Advantage of Committing Challenges in Zero-Knowledge Protocols

ePrint Report: On The Practical Advantage of Committing Challenges in Zero-Knowledge Protocols

David Naccache, Ofer Yifrach-Stav

The Fiat-Shamir transform is a classical technique for turning any zero-knowledge $\Sigma$-protocol into a signature scheme.


In essence, the idea underlying this transform is that deriving the challenge from the digest of the commitment suppresses simulatability and hence provides non-interactive proofs of interaction.


It follows from that observation that if one wishes to preserve deniability the challenge size (per round) must be kept low. …

challenge challenges digest eprint report fiat knowledge protocol protocols report sigma signature transform